Electric burglar alarm system



A 7, 1954 F. E. POULSON 2,636,909

ELECTRIC BURGLAR ALARM SYSTEM Filed Dec. 28. 1949 PROTEC 77V CIRCUITS Patented Aug. 17, 1954 2,686,909 ELECTRIC BURGLAR ALARM SYSTEM Frank E. Poulson,

Chicago, 111., assignor to Certified Burglar Alarm Systems, Incorporated, Chicago, 111., a corporation of Illinois Application December 28, 1949, Serial No. 135,414.

Claims.

The present invention relates to an alarm system and has special reference to a burglar alarm system which gives a warning signal in case of unauthorized entry to the premises protected thereby.

More particularly this invention relates to a burglar alarm system in which severing of the cable, containing. the leads supplying current to the alarm signal will itself result in setting off the alarm,

The present burglar alarm, system preferably comprises an inside instrument box having a relay or other circuit control means and a source of energy such as a battery, and an outside signal box having a bell, siren, or other warning signal therein. Thesignal is connected to he energy source and relay by conductors extending between the two boxes, so that whenever the relay contacts are closed the signal is actuated.

The relay windingis in series with a source of energy and one or more protection circuits suitably arranged to guard doors, windows, and freuently the walls of premises and also the instrument and signal boxes. As long as the protection circuits remain closed the relay winding is energized and the relay is held up. However,

whenever any of the protection circuits are broken or crossed, such why an unauthorized person attempting to enter the premises, the

relay contacts close and the signal sounds.

While such a system is generally sufiicient protection, it may be rendered inoperative by anyone locating and severing conductorsconnecting the inside control instrument and outside signal boxes. To overcome this deficiency the signal box of the present system is provided, with an auxiliary protection circuit including a source of energy, control means, such as a relay, and the alarm signal. The winding of this last relay is connected to the source of energy in the inside instrument box by conductors in thecable, one of which may be one of the conductors connecting the source of energy in the instrument box to the signal. Normally the relay contacts in the signal box are held up, but when the cable and conductors are severed, these contacts close and the alarmsounds.

An object of the present invention is to provide an effective burglar alarm system of Wide application.

Another object is to provide such a burglar alarm system which will sound a warning signal if any of the protection circuits are broken or crossed. l l

A still further object is to provide a burglar alarm system in which the alarm signal Will be instrument box, which is normally situated inside the building or premises to be protected, preferably has therein a source of energy, such as a battery 13 and a relay l4 comprising contacts I5 and awinding it. Other suitable circuit control means may be employed in place of therelay M. A second source of energy, such as a battery I! for the various protection circuits is also arranged in the instrument box or may be located elsewhere the protected premises.

The signal .box IE is situated outside the premises where the alarm maybe most easily heard when actuated, suchas over the front door to the premises. A warning signal of any suit able type may be employed, that shown being a hell I 8. A siren would be equally suitable, and a visualsignal may be used in place of or in addition to the audible signal.

A cable {9 extends between the instrument and signal boxes andhas therein a plurality or conductors, three being shown for purposes of illustration and numbered Ell, 2|, and 22. As shown in the figure, two of the conductors 2t and 2| connect the bell E8 in circuit with the relay contacts l 5 and the battery 13. Thus, whenever the contacts l5 are closed, the bell I 8 will be sounded.

The winding I6 ofthe relay it is connected in series with the battery I! and the usual protection circuits 23, 24,. and 25 provided for the various doors, windows, boxes, and walls desired to be protected. These protection circuits are connected in series so that a break in any one will prevent the flow of current in the circuit 23 leading into the instrument box. As thus arranged, the winding is energized and normally holds the relay up until one of the protection circuits is broken, when the contacts l5 will close. A sealed and protected master switch is usually provided by means of Which the alarm system may be rendered inoperative when not required for protee tion purposes.

With a system as above described it is possible to render the alarm inoperative by severing the cable {9 and the conductors therein, thereby preventing energization of the bell 18. To prevent this, a monitor warning circuit may be provided in the signal box. Such circuit preferably includes a battery 26 or other suitable source of energy and circuit control means such as a relay 271 located in the outside signal box. Conductors 28 and 29 connect the relay contacts 38 and the battery 26 with the signal. Thus whenever the contacts 30 are closed the bell or other signal will be energized and actuated. The winding 3! of the relay 2! is preferably connected to the battery 13 by one of the conductors connecting this battery to the bell, such as the conductor 2 l and a second conductor 22. The relay winding 3! normally holds up the relay 2''. However, severance of the cable l9 and either of the conductors 2| or 22 or crossing of these conductors will result in the closing of the contacts 30 and sounding of the bell I8.

While the cable 19 is shown as having three conductors therein, a greater number may be provided so that the conductors connecting the bell 18 to the battery [3 may be independent of those connecting the relay coil to the battery l3. In either construction, severance of the cable IQ and the conductors therein will result in the alarm being sounded.

In any event the arrangement shown is simple and extremely useful because it is necessary to disrupt one of the two conductors 2t and 2| of n the bell circuit to disconnect the bell l8. By using one of-thes-e conductors with conductor 22 as the circuit for the control 2'1, the possibility of opening this circuit when cable 19 is cut is thereby greatly increased and the ability of defeating the efiectiveness of control Z'l is thereby de creased.

While I have shown a particular embodiment of my invention, it will be understood that I do not wish to be limited thereto since many modifications may be made, and I therefore contemplate, by the appended claims, to cover any such modifications as fall within the true spirit and scope of my invention.

I claim:

1. An alarm system of the character described comprisin in combination an instrument box having therein a portion of a protection circuit including energization means a source of energy for a warning signal and a relay having the winding thereof in said protection circuit biased to closed position and normally maintained in open position by energization of a protection circuit, a signal box having a warning signal therein, a cable extending between said boxes having a plurality of conductors, certain of said conductors Connecting, said signal in circuit with said energy source and said relay, said signal box having therein in circuit with said signal a source of energy and a solenoid switch for being moved to open position when energized, said switch means being connected to the source of energy in said instrument box by conductors in said cable for normally maintaining said switch means in open position 2. An alarm system of the character described. comprising in combination a protection circuit including energization means, an instrument box having therein a battery for a warning signal and a relay biased to closed position with thewinding thereof in said protection circuit, a signal box having a warning signal therein, a cable extending between said boxes having a plurality of conductors, with certain of said conductors connecting said signal in circuit with said battery and said relay, said signal box having therein a second battery and a relay biased to closed position in circuit with said signal, said last relay having its winding connected to the batteryin said instrument box by conductors in said cable for normally maintaining said last signal circuit open.

3. An alarm system of the character described comprising in combination a protection circuit energization means, an instrument box having therein a battery for warning signal and relay biased to closed position with the winding thereof in said protection circuit, a signal box having a warning signal therein, a cable extending between said boxes having at least three conductors therein with a pair of said conductors connecting said signal in circuit with said battery and said relay, said signal box having therein a second battery and a relay biased toclosed position in circuit with said signal, said last relay having its winding connected to the battery in said instrument box by one of said pair of conductors and an additional conductor in said cable for normally maintaining said signal circuit open.

l. An alarm system of the character described comprising in combination an instrument box having therein a. portion of a protection circuit having energization means, an energy source for a warning signal and circuit control means biased to closed position and arranged to be maintained in open position by energization of said protection circuit, a signal box having a warning signal therein, a cable extending between said boxes having a plurality of conductors, certain of said conductors connecting said signal in circuit with said energy source and said circuit control means, said signal box having therein a source of energy and circuit control means biased to closed posi+ tion in circuit with said signal, the circuit control means in said signal box being connected to the source of energy in said instrument box by conductors in said cable for normally maintaining said circuit control means in open position.

5. An alarm system of the character described comprising in combination an instrument box having therein a portion of a protection circuit having energization means, an energy source for a warning signal and a relay having the winding thereof in said protection circuit biased to closed position and normally maintained in open position by energization of said protection circuit la signal box having a warning signal therein, a cable extending between said boxes having a plurality of conductors, certain of said conductors connecting said signal in circuit with said energy source and said relay, said signal box having therein a source of energy and circuit control means biased to closed position in circuit with said signal, the circuit control means in said signal box being connected to the source of energy in said instrument box by conductors in said cable for normally maintaining said circuit control means in open position.

References Cited in the file of this patent UNITED STATES PATENTS 

